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Check whether a string is not null and not empty
... && fails, thus ensuring you will not get a null pointer exception from str.isEmpty() if str is null.
Beware, it's only available since Java SE 1.6. You have to check str.length() == 0 on previous versions.
To ignore whitespace as well:
if(str != null && !str.trim().isEmpty())
...
How to declare and add items to an array in Python?
...se append
my_list.append(12)
To extend the list to include the elements from another list use extend
my_list.extend([1,2,3,4])
my_list
--> [12,1,2,3,4]
To remove an element from a list use remove
my_list.remove(2)
Dictionaries represent a collection of key/value pairs also known as an as...
Declaring variables inside loops, good practice or bad practice?
..., whose sole purpose is to declare variables which must retain their value from one loop to another. This typically includes the loop counter itself.
{
int i, retainValue;
for (i=0; i<N; i++)
{
int tmpValue;
/* tmpValue is uninitialized */
/* retainValue still ha...
Why must wait() always be in synchronized block
...s true:
You can get spurious wakeups (meaning that a thread can wake up from waiting without ever having received a notification), or
The condition can get set, but a third thread makes the condition false again by the time the waiting thread wakes up (and reacquires the monitor).
To deal wit...
Check status of one port on remote host [closed]
...known ip:
nmap -A 192.168.0.5/32 -p 23
For example, look for open ports from 20 to 30 on host.example.com:
nc -z host.example.com 20-30
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npm install private github repositories by dependency in package.json
...he npm package module exists):
"dependencies" : {
"name": "*"
}
Taken from NPM docs
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Why should I use Hamcrest-Matcher and assertThat() instead of traditional assertXXX()-Methods
...easier to read, but once the assert fails, you'll get a good error message from assertThat, but only a very minimal amount of information from assertTrue.
assertThat will tell you what the assertion was and what you got instead. assertTrue will only tell you that you got false where you expected tr...
How to get VM arguments from inside of Java application?
...t for -client and -server. Thus, if you infer the -client/-server argument from the VM name and add this to the runtime management bean's list, you get the full list of arguments.
Here's the SSCCE:
import java.util.*;
import java.lang.management.ManagementFactory;
class main {
public static voi...
Programmatically Lighten or Darken a hex color (or rgb, and blend colors)
... blend it with a second color, and can also pass it right thru but convert from Hex to RGB (Hex2RGB) or RGB to Hex (RGB2Hex). All without you even knowing what color format you are using.
This runs really fast, probably the fastest, especially considering its many features. It was a long time in the...
Intercepting links from the browser to open my Android app
...android.intent.action.VIEW of category android.intent.category.BROWSABLE.
From Romain Guy's Photostream app's AndroidManifest.xml,
<activity
android:name=".PhotostreamActivity"
android:label="@string/application_name">
<!-- ... -->
<...